Muffler tube and bushing connection

ABSTRACT

The inlet and/or outlet end of an exhaust muffler contains a bushing which in one form of the invention is provided with an expanded annular rib to receive an expanded portion of a gas flow tube and thereby serve to hold the tube in axial position; and, in a second form of the invention, has an expanded portion which receives an expanded portion on a gas flow tube so that additional axial space is provided to receive a tailpipe or an exhaust pipe.

United States Patent Inventor John H. Foster Clarke Lake, Jackson, Mich. Appl. No. 823,329 Filed May 9, 1969 Patented Sept. 28, 1971 Assignee Tenneco Inc.

Houston, Tex.

MUFFLER TUBE AND BUSHING CONNECTION 3 Claims, 1 Drawing Fig.

U.S.Cl 181/61,

18 N72 lnt.Cl F0ln 7/18 Field of Search 181/61, 70,

[56] References Cited UNITED STATES PATENTS 2,251,369 8/1941 Moss 181/48 2,573,474 10/1951 Marx..... 181/47 3,106,984 10/1963 Carter 181 /57 Primary ExaminerStephen J. Tomsky Attorney-Harness, Dickey & Pierce ABSTRACT: The inlet and/or outlet end of an exhaust muffler contains a bushing which in one form of the invention is provided with an expanded annular rib to receive an expanded portion of a gas flow tube and thereby serve to hold the tube in axial position; and, in a second form of the invention, has an expanded portion which receives an expanded portion on a gas flow tube so that additional axial space is provided to receive a tailpipe or an exhaust pipe.

MUFFLER TUBE AND BUSHING CONNECTION SUMMARY OF THE INVENTION It is the purpose of this invention to improve the bushing and gas flow tube connection in a muffler and the invention accomplishes this by means of an expanded portion in the header bushing in which portion is fitted the internal gas flow tube.

DESCRIPTION OF THE DRAWINGS The drawing shows a longitudinal cross section through a typical muffler for use in automotive exhaust systems which embodies the invention in both its forms.

DESCRIPTION OF THE INVENTION The muffler 1 has a tubular shell 3 which is preferably oval in cross section. The inlet end of the shell 3 is closed by an inlet header 5 which has an inlet opening formed by an annular inwardly extending flange 7. The outlet end of the shell 3 is closed by an outlet header 9 which has an outlet opening that is formed by an annular flange l1. Mounted in and spotwelded to the flange 7 is an inlet bushing 13 which is slotted at 15 so that it may be clamped to the end of an exhaust pipe. Mounted in and spotwelded to the outlet flange 11 is an outlet bushing 17 which is slotted at 19 so that it can receive and be clamped to a tailpipe in an exhaust system.

The space within the shell 3 is divided into three longitudinally separated chambers 21, 23, and by means of transversely extending partitions 27 and 29 which have annular peripheral flanges 31 that are welded to the shell 3. The partition 27 has three openings defined by annular flanges 33, 35, and 37 while the partition 29 has two openings defined by annular flanges 39 and 41. The flanged opening 33 interconnects the chamber 21 and 23 while the flange 39 supports and is spotwelded to a tuning tube 43 that extends within the chamber 25 to provide the sole connection between that chamber and chamber 23 and thereby serve with the volume of chamber 25 to act in accordance with the Helmholtz formula to silence a predetermined frequency.

The upstream end of an inlet gas flow tube 45 is supported in the bushing 13 and the downstream end opens into chamber 23. The tube 45 has a first patch of louvers 47 and a second patch of louvers 49, the latter opening into the chamber 23. The first patch 47 is surrounded by a shell 51 that forms a closed spit chamber 53 which acts with the louvers to attenuate high frequency noise and roughness. The shell 51 is supported in the flange 37.

The upstream end of an outlet tube 55 is supported in the flange and the tube has a patch of louvers 57 opening into the chamber 23 and a patch of louvers 59 which is surrounded by a shell 61 that forms a closed chamber 63 around them and thereby acts as a spit chamber to attenuate high frequency noise and roughness. The shell 61 is supported in flange 41 and the downstream end 65 of the tube 55 is expanded in diameter at 66 and supported in an expanded or enlarged diameter portion 67 of the outlet bushing 17. The expanded portions 66 and 67 are sized so that the internal diameter of the tube end portion 65 is no smaller than and preferably the same diameter as the internal diameter of the outer uniform diameter portion 69 of the bushing 17 so that a tight fit is obtained.

The inlet bushing 13 has an expanded or enlarged diameter portion 71 which is preferably in the form of a ring located inwardly of the outer uniform diameter portion 73 and also located outwardly of the header 5. The end 75 of the inlet tube 45 is expanded into a tight fit with portion 71 by a suitable tool into the ring 71 and it is apparent that this provides a connection between the tube 45 and the bushing 13 that fixes the axial position of the tube and thereby eliminates the need to spotweld the tube 45 to the bushing 13. At the outlet bushing end 17 the expanded tube and ring 71 construction can be used, if desired, or in the particular embodiment illustrated the tube 65 can be spotwelded to the bushing 17 to fix it in axial position.

In operation, gas enters the inlet bushing 13 and flows through the tube 45 to the chamber 33 where it reverses direction to flow through the opening 33 into the chamber2l and then through the outlet tube 55 to the outlet bushing 17. As already indicated, attenuation of high frequency and roughness occurs in the spit chambers 53 and 63. In addition, attenuation of medium to high frequencies occurs by virtue of the acoustic connection of louver patches 49 and 57 with the chamber 23. A predetermined low frequency may be attenuated by means of the resonator tuning tube construction provided by tube 23.

The ring 71 simplifies and reduces the cost of the tube to bushing connection by eliminating spotwelding. The expanded size of tube end 65 enables an exhaust pipe or tailpipe (not shown) to be inserted as far as the shoulder of section 66, thereby increasing the strength of the connection and the flexibility of the muffler.

I claim:

1. In an exhaust muffler having a tubular shell and a header closing an end of the shell, said header containing an annular flange defining an opening, a bushing fitting in said annular flange and firmly secured to it, one end of the bushing being of uniform diameter and extending outside the shell and adapted for connection to a pipe in an exhaust system, the other end of the bushing extending inside the shell, said bushing having an enlarged diameter portion located inwardly of and larger than the uniform diameter portion, and a gas flow tube inside the shell having an enlarged end portion tightly fitting inside the enlarged diameter portion of the bushing, said enlarged diameter portion of said bushing comprising an annular ring of arcuate cross section located between the ends of the bushing and the enlarged end portion of the tube being arcuate and fitting inside said ring to fix the axial position of the tube rela tive to the bushing.

2. A muffler as set forth in claim 1 wherein the enlarged end portion of the tube is at and includes the end tip of the tube.

3. In an exhaust muffler having a tubular shell and a header closing an end of the shell, said header containing an annular flange defining an opening, a bushing fitting in said annular flange and firmly secured to it, one end of the bushing being of uniform diameter and extending outside the shell and adapted for connection to a pipe in an exhaust system, the other end of the bushing extending inside the shell, said bushing having an enlarged diameter portion located inwardly of and larger than the uniform diameter portion, and a gas flow tube inside the shell having an enlarged end portion tightly fitting inside the enlarged diameter portion of the bushing, said enlarged portion of said bushing extending to the inside end thereof and the internal diameter of the enlarged end portion of the gas flow tube being substantially the same as the internal diameter of said uniform diameter outside end portion of the bushing. 

1. In an exhaust muffler having a tubular shell and a header closing an end of the shell, said header containing an annular flange defining an opening, a bushing fitting in said annular flange and firmly secured to it, one end of the bushing being of uniform diameter and extending outside the shell and adapted for connection to a pipe in an exhaust system, the other end of the bushing extending inside the shell, said bushing having an enlarged diameter portion located inwardly of and larger than the uniform diameter portion, and a gas flow tube inside the shell having an enlarged end portion tightly fitting inside the enlarged diameter portion of the bushing, said enlarged diameter portion of said bushing comprising an annular ring of arcuate cross section located between the ends of the bushing and the enlarged end portion of the tube being arcuate and fitting inside said ring to fix the axial position of the tube relative to the bushing.
 2. A muffler as set forth in claim 1 wherein the enlarged end portion of the tube is at and includes the end tip of the tube.
 3. In an exhaust muffler having a tubular shell and a header closing an end of the shell, said header containing an annular flange defining an opening, a bushing fitting in said annular flange and firmly secured to it, one end of the bushing being of uniform diameter and extending outside the shell and adapted for connection to a pipe in an exhaust system, the other end of the bushing extending inside the shell, said bushing having an enlarged diameter portion located inwardly of and larger than the uniform diameter portion, and a gas flow tube inside the shell having an enlarged end portion tightly fitting inside the enlarged diameter portion of the bushing, said enlarged portion of said bushing extending to the inside end thereof and the internal diameter of the enlarged end portion of the gas flow tube being substantially the same as the internal diameter of said uniform diameter outside end portion of the bushing. 